JLog is a Prolog interpreter written in Java. It is fast and perfectly suited for education. It includes source editor, query panels, online help, animation primitives, and a GUI debugger. JScriptLog is Prolog in JavaScript.

Linguistic Tree Constructor (LTC) is a tool for drawing lingusitic syntax trees. The user can define their own node categories, and can label each node with labels, also definable by the user. LTC supports "generic", X-Bar and RRG trees.

The ECLiPSe Constraint Logic Programming System is designed for solving combinatorial optimization problems, for the development of new constraint solver technology and their hybrids, and for the teaching of modelling, solving and search techniques.

Flora-2 is a powerful knowledge representation and reasoning system designed for building knowledge-intensive applications. It is based on F-logic, HiLog, Transaction Logic, and also supports defeasible reasoning. Applications include intelligent agents, Semantic Web, ontology management, and more.

The Prolog Expert System Shell (PESS) is a software that generates ES using basically two components: Knowledge Base, used by the ES to guide its decisions making, and Inference Machine, cable of collection the rules and generating new facts.

The Yap Prolog System is a ISO-compatible high-performance Prolog compiler. Yap is widely considered one of the fastest available Prolog systems. Yap supports coroutining, CLP(QR), CHR, and depth-bound search. Tabling and parallelism are in development.

A Prolog expert system supporting querying and extending the knowledge base from a command-line interface using a format oriented on natural language, with the aim of being maintainable by the domain expert (i.e. without requiring programming skills).

OpenSHORE is an XML based Semantic Document Repository (SDR) with a free definable meta model that builds up a semantic network from sections and relations in documents. The acronym SHORE means Semantic Hypertext Object Repository.